Buried pipe lines asme b31.3

[gravitate]

I do not have a copy of ASME B31.3 does anyone know if it is worth getting hold of one as we are trying to determine the requirements of buried pipework when it goes under roads and if it should be in sleaves? Also we are trying to find out the minimum depth it should be.

 

[LittleInch]

It is always / mandatory to have a copy of the code you are designing or installing to.

However for buried pipework B 31.3 offers very little in the way of requirements for buried pipe as far As I know or can see. Normally pipelines are buried and hence all these aspects are covered in B 31.4 or B 31.8 (Liquid or Gas). Normally pipes under roads are not sleeved anymore, but direct buried, however for pipework inside plants, ducts and duct banks are common. If it is just the pipe being buried then inside a plant it will depend on the surface loading, outside a plant I would recomend a min 1.2m.

Use API 1102 to calcualte your stress for buried pipelines and be aware that a road crossing effectively anchors the pipe so a stress analysis may be required due to the loss of flexibility of the pipe.

All a little vague so can't advise further.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[stanweld]

B31.3 does not address your stated underground issues. You will have to address Jurisdictional requirements or B31.4/B31.8.

 

[uaepiping]

Check ASME B31.3 interpretation 21-07.

 

[MrReilly]

API 1102 has good design rules for road crossings.

 

[BigInch]

You may or may not need a casing. Casings are not preferred, due to corrosion issues. Extra burial depth, pipe wall thickness, or mechanical protection in the form of a concrete slab between pipeline and road surface could be options. If it is a public road, your B31.3 code may not apply at all, or you may have to take the most conservative conditions of each code.

Independent events are seldomly independent.